Hi.

The installed 7-pin trailer connector on my Fabia I combi (6Y5) is very flaky, and my plan is to replace it with a new 13-pin connector, which most trailers have now and not need to to use the bulky 7- to 13-pin adapter

However when the old connector was removed i noticed there was an extra cable going to a little switch which is grounded (pin 3) when a trailer is not connected (i guess).

What is this extra cable used for? Is it possible to just rewire the normal 7-pin to a 13-pin connector?

I do not need constant power or ignition switched power to the trailer.

I came across this before in my son in laws vw caddy. Never seen one before. It disables the cars rear fog light and also the rear parking sensors plus a few other things to do with stability control. You can get a 13 pin socket with microswitch.

Alasdair

Ahh, thanks for the information Alasdair.

It makes sense to disable these functions with a trailer connected.

Actually I found a diagram from a trailer manufacturer, and it seems as the standard specifies that pin 12 and 13 is interconnected in the trailer, to indicate that a trailer is connected to the car. This might actually be used in conjunction with a switching relay (NO to NC) to disable these functions.

I will do some tests and report back.

Thanks again.